The Advanced Muon Facility: a proposed multi-purpose muon facility at Fermilab

Abstract

Charged lepton flavor violation (CLFV) is expected in a diverse set of new physics scenarios. The current generation of experiments probe CLFV in the muon sector in three complementary channels: $\mu^-N \rightarrow e^- N$ (Mu2e, COMET), $\mu^+ \rightarrow e^+ \gamma$ (MEG-II), and $\mu^+ \rightarrow e^+e^+e^-$s (Mu3e). These experiments aim to enhance existing limits by several orders-of-magnitude in the coming decade and offer discovery potential to many new physics models. The proposed Advanced Muon Facility (AMF) would be a multi-purpose muon facility based at Fermilab and introduces an innovative approach based on a muon storage ring to enable a full suite of muon CLFV experiments. AMF would host CLFV experiments with sensitivities orders-of-magnitude beyond the present era. In the event of a signal in these currently planned experiments, AMF would enable additional measurements to elucidate the nature of the new physics observed. The design and R$\&$D for AMF is in its infancy. This article outlines the motivations for AMF, detailing on-going R$\&$D efforts, and highlighting potential synergies with the proposed muon collider.